You know her (and love to loathe her): the ultra-enviable Hollywood mom, propping little Odin or Coco on her hip while she careens around Beverly Hills in her 4-inch Roland Mouret heels and size triple-zero jeans. As if pregnancy and its aftermath are, like, no big deal.

In her new book, “How To Look Hot in a Minivan,” Janice Min, former Us Weekly editor and now the editorial director of the Hollywood Reporter, reveals everything you want to know about celeb moms, from the insanity of their 1,200-calorie-a-day diets to their affinity for postnatal Botox.

Famous moms, she says, keep up appearances with serious effort and a coterie of assistants. “None of these celebrity moms — I call them momshells in the book — are doing it alone,” says Min, a mother of three who was inspired to write the book by her own experiences as a new mom.

While “Minivan” touches on extremes like sob-inducing workouts and postpartum tummy tucks, Min reminds readers that celebrities are paid to sell fantasy. “Luckily, we don’t need to be that crazy,” she says, “but we can learn just a few things from them to make our lives easier.”

1. They do insane workouts

Heidi Klum hit the runway within weeks after giving birth in 2009, but getting lingerie-ready wasn’t easy. “She talked about working out for four hours at a time to make that happen,” Min says. “The reason they look so good is because they’re putting in the effort.” Kate Hudson, who notoriously gained more than 65 pounds during her first pregnancy, was another celeb to hop on the hard-core workout train. “[She] cried during those workouts,” Min says of Hudson’s three-hour training sessions. The star endured 10 weeks of brutality to get back to her pre-baby weight.

2. They follow super-strict diets

“Some of these mothers will do crazy things,” Min says, noting that extreme cleanses like the Clean program Gwyneth Paltrow touts are the norm. “But for the most part, it’s pretty simple: They really moderate what they eat.” In “Minivan,” nutritionist Keri Glassman, who’s worked with Drew Barrymore, says she urges clients to nix processed foods and stop eating off of their kids’ plates, which can cut hundreds of calories. “These celebrity moms have an incredible discipline about them,” Min says. “They don’t sneak a lollipop in the car, they don’t finish the breadbasket.”

3. They get Botox

Gone are the days when Botox was taboo. “People talk about it quite openly,” says Min, who jokes in her book that, in LA, it’s “as commonplace as getting a blow-out.” Moms who admit to getting a prick here and there include Daisy Fuentes, Jenny McCarthy and Vanessa Williams. The pricey procedure can cost anywhere between $300 and $1,000 per session, but it may be one indulgence Virginia Madsen can save on; the actress is such a fan that she’s a celebrity spokeswoman for it!

4. They wear Spanx

“If you can’t exercise that extra muffin-top off, this is a way to pretend you don’t have it anymore,” Min says. She noticed the must-have shapewear’s growing popularity several years ago, at about the same time Hollywood moms started flaunting their post-pregnancy bodies. “All of a sudden you had moms [on the red carpet] saying ‘I’m wearing two pairs of Spanx!’ ‘I couldn’t be out here if it weren’t for my Spanx!’ ” Paps have caught Katie Holmes and Jennifer Lopez with theirs peeking out, but stars like Julie Bowen aren’t worried about being discreet. “You can’t get her to stop talking about Spanx!” Min says.

5. They go under the knife

While Patricia Heaton and Lisa Rinna have always been candid about getting work done (Heaton got a tummy tuck and breast lift; Rinna has implants and cheek fillers) a lot of stars don’t talk about plastic surgery. But does Min think more moms are getting nips and tucks than are fessing up to it? “One-hundred percent,” she says. “If you drive around Beverly Hills, there’s a plastic surgery office on every corner. Someone’s paying for that!”

6. They put a lot of time (and money!) into their wardrobes

Reese Witherspoon, Halle Berry and Jessica Alba all landed on Min’s best-dressed moms list. Like most starlets, they have the luxury of working with stylists — but as these wardrobe czars told Min, even stars use tricks to keep their hot-mom status. Long scarves draped around the upper body and statement jewelry that draws attention away from post-baby bulges are both trending in Hollywood. Another tip came courtesy of Spanx creator Sarah Blakely. “She said the worst thing to do when you’re trying to look good and feel good is to squeeze back into your [pre-baby] clothes,” says Min. Blakley urges women to buy clothes that fit, even if it means getting a bigger size.

7. They drop bank on designer mom accessories

“All the celebrity moms have a great diaper bag,” Min says, citing Jennifer Garner and Nicole Richie among those spearheading the trend. Highlighted in the book are Mia Bossi’s “Maria” bag ($400) and Min’s personal favorite, Rosie Pope’s London Shopper ($365). “[These] aren’t a fortune,” says Min “but [they] save you from looking like you’re headed to the mall in your minivan!”